Surveillance of sorghum armyworm Mythimna separata (Walker) and its natural enemies in transitional region of Dharwad.

Abstract

Surveillance studies conducted on the sorghum armyworm Mythimna separata (Walker) and its natural enemies revealed that the pest actively was from June to December during 1992 and up to October during 1993. The activity attained peak during September with 59.42 and 34.25 per cent incidence during 1992 and 1993, respectively. Nine parasitoids were recorded parasitizing 18.16 and 17.55 per cent larvae during 1992 and 1993, respectively. The parasitoids Pseudogonia sp ., Compsiiura sp . and Goryphus sp . were active in the early part of the season which were followed by C otesia ruficrus and Exorista xanthaspis in the middle of the season (September-October). Correlation studies on parasitism indicated significant positi ve correlation with maximum temperature (r=0.645) and significant negati ve correlation with minimum relative humidity (r=-0.693) during 1992 and non significant correlation with abiotic factors during 1993.